Internal-combustion engine.



PATENTED SEPT. 8, 1908.

0: N. SCOTT. INTERNAL COMBUSTION BZQTGINE.

APPLICATION EILED JAN, 23, 1905.

2 SHEETS-SHEET 1.

magma No. 898,271. PATENTED SEPT. 8, 1908.;

G. N. SCOTT. INTERNAL COMBUSTION ENGINE.

APPLICATION FILED JAN. 23:. 1905.

2 SHEETS-SHEET 2.

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r-s c 8 1g P- A QVihwao' co .ju vrrnn s riirrr cream oE IQ f CLARENCE N.soorr, or BUFFALO, NEW YORK, ASSlGNOR TO nzriurriiriomi. strum PUMPCOMPANY, or NEW roan, Y., A CORPORATION or NEW JERSEY.

INTERNAL-COMBUSTION ENGINE v Specification of Letters Patent.

Patented S ep tJ'S, 1908.

Application filed January 23, 1905. Serial No. 242,280.

To all whom it may concern:

Be it known that I, CLARENCE N. SCOTT, asubject of Great Britain,residing at Buffalo, county of Erie, and State of New York, haveinvented certain new and useful "'l11)1)10-*6- [nients in Internal-Combustion Engines, fully described and represented in the followingspecification, and the accompanying draw 11igs, forming a part of thesame.

This invention relates to an improvement in compound internal combustionreciprocatingengines ofthat class known as four cycle engines in whichthe piston makes one ower or working stroke in two revolutions, t e obi5ject being to provide an etlicient and economieal compound engine ofthis class, and further to'p'rovide for the use of light trans; missionparts fully utilized in transmitting the net load.

The invention consists in novelcombina tions and arrangements ofcylinders in a compound four cycle internal combustion engine, as fullydescribed and claimed.

In the accompanying drawings forming a zapart .of this specification,the invention is "shown as applied in a preferred form of enl v Figure 1isa side elevation of thelow presi sure sidefof the-engine. Fig. 2 is aplan view goof the engine. Fig. 3 is a cross section on any of the lines3 of Figs. 1 and 2. Fig. 4 is a sectionof the air and gas tank andpassages on line 4 of Figs. 2 and 3. Fig. 5 is a diagram of the cyclein" the four cylinders. -Inthedrawings,A,A. are two double actinghighpressure cylinders and B, B two double actinglowrcssurecylinders,thetwohighpressurecyl'inc ers being arranged tandem onone side of the engine with their pistons a, a connec ted by piston rod(1 and connecting rod D tothe cranlr E on the engine shaft F, and thetwo' low pressure cylinders B, B being arranged tandem alongside therespective liigh'pressure cylinders, with their pistons a, I)" connectedby the pistonrod G and connecting rod H to crank I on shaft F, the "two.cranks E, l'being located in the. direction of rotation at approximately180 from each other. Ahorizontalengine is shown, but the invention isapplicable also to vertical en gines,

" The high pressure cylinders are provided at each'end'with inlet valves0, which are shown asyalvesof common form operated by valve stems 10,levers 11 and cam rods 12 from suitable cams on cam shaft 13 the chargebeing-admitted to the chamberabove the inlet; valves 0 through mixingvalve doi" anyconimon or suita.bliform towhichthe air and gas p'assfroinair. passages 1 and gas passages 2, connecting with the air and gas tanklitlirough air. and gas passages 1 4, 15, extending dblOllg'lllG tank.The gas tank- K, in the .form shown, co 'isists of a circular tankmounted between and above the engine cylinders, and divided by a pres--(55 sure equalizing piston lo -into' air andgas chambers 17, 18, thepassage 14 connecting with the former and the passage-1 5 with thelatter. The gas chamber "18 isnconnected with a gas chamber 1-9.tidoughvalve 3,"in which chamber 19 gas is maintained at a pressurehigher than the maxiu'iun'i pressure required in the chamber-1:8 by anattached or independent gas pump and regula torsol? any common orsuitable form. '.l.hispvalve 3 is 7 opened by the piston 16 engaging rod20 when the piston is moved to the left-,- sufii ciently, so as to admitgasfrom the chamber -19 to the chamber 18 when required,- and thusmaintain the desired equilibrium of air and gas pressure in the chambers17, 18-. 1 .Anair release valve t operated by the piston 16 through rod21 is shown for limiting the volume and pressure of air in chamlj er 17.r I

Each end of the high pressure cylindcrscxhausts into the correspondingend ofthe adjacent low pressure cylinder through pas sages L which thusact. asexhaust passages for the high pressure cylinders and inlet pas-.sages for the low pressure. cylindersjand these passages L are shown ascontrolled by valves c actuated by rods22 andlevers 23 from suitablecams on cam shaft Each end of each .low pressure cylinder actsalternately as a pump to compress air into tho-tank K, and as a workingcylinder with the piston actuated by theexhausgfrom its high pressurecylinder. Airis admitted to the low pressure cylinders through airpassages M, communicating with .the, atinosphere, and shown ascontrolled-by the inlet valves f, operated by valve rods 24, levers 25and cam rods 26 from suitable cams. on the cam shaft 27. Air isdelivered from thelowr pressure cylinders to thetank K throu h passagesN controlled by automatic va ves g, which valves 0' en when thepressure-in the cylinder excee s-that in the tankyas iisu'al in suchautomatic valve constructions-.12. I.

The low pressure cylinders exhaust through 1 10 passages O to theatmosphere or otherwise, these passages being shown as controlled byexhaust valves it operated by stems 28 and levers 29 from suitable camson the cam shaft 27. i t

It is desirable that some form of governor control he used on the highand low pressure suction stroke, and the low pressure cylinders beingprovided with air cut off valves is, which, when the air required forthe combustion of the gases has been admitted, close and preventadmission of air to the low pressure cyl .inders during the remainder ofthe low pres-- sure suction stroke, these valves being actuatedindependently of the main valves by suitable connections from a governorof any desired form. As shown, the governor P actuates cam shafts 30,31, which control the valves-i, A? through cam rods 5, 6, and triplevers 7, 8. Any other suitable form of governor control may be used,however, as well as any other form of valves and valve actuatingdevices, these forming no part of the resent invention, the form shownbeing selected only for purpose of illustration and as one form of manysuitable for use in an engine embodying the invention. The illus trationof the valves is largely diagrammatic, actuating springs being omitted,as such 'main and cut off valve constructions are wellknown. Igniting'devices of any suitable form may be used, or combustion secured in anymanner desired.

It will be understood that high pressure inlet valves 0 are open duringthe suction stroke of the high pressure pistons and closed during therest of the cycle; the combined exhaust and inlet valves 6 are openduring the exhaust stroke of the high pressure pistons and thecorresponding working stroke of the low pressure cylinders and closedduring the rest of the cycle; the low pressure air inlet valves f areopen during the suction stroke of the low pressure cylinders and remainopen during the compression or delivery stroke and are closed during therest of the cycle and the exhaust valves h of the low pressure cylindersare openduring the exhaust stroke of the low pressure cylinders andclosed during the rest of the cycle.

The cycleon which this engine will preferably operate, is illustrateddiagrammatically in Fig. 5, Which shows the stroke in each end of eachcylinder throughout the cycle. In this figure, the strokes are indicatedby letters as follows :"P indicates the power stroke, obtained in thehigh pressure cylinders from the compressed charge and in the lowpressure cylinders by further expansion of the exhaust from the highpressure cylinders. E indicates the exhaust stroke, that is, the exhaustof the high pressure cylinders to the low ressure cylinders and theexhaust of the ow pressure cylinders to the atmosphere. S indicates thesuction stroke during'whichthe charge is admitted into the highpressurecylinders and air is drawn into the low pressure cylinders; C indicatesthe compression stroke by which the charge, already under considerablepressure, is furthercompressed in the hi h pressure cylinders and air iscompressed from the low pressure cylinders into the tank K. From thesediagrams of Fig. 5, it will be seen that there is one and only one poweror impulse stroke on each crank at each stroke or movement of thepistons in either direction, and that the initial load on each highpressure stroke is directly resisted by the initial back pressure orexpansion load on the same or a connected piston, so that the maximumload to be trans mitted is only that due to the high pressure initialpro ulsion load minus the high res sure initial back pressure orexpansion oad. The results secured by these features of the cylinderarrangement and cycle described are very im ortant in the constructionand operation 0 the engine, as they enable the size and weight of thecrank shaft and fly wheel, the parts transmittin the ower from thepistons to the crank shaft,.an the framing connecting the crank shaftjournals with the power cylinders to be reduced. The size and weight ofall these parts depend upon the maximum initial net propulsion load andthe regularity of the turning moment, and with the cylinder arrangementand cycle above described, the total net initial load to be transmittedto" the crank shaft on any stroke is reduced so far as possible withoutreducing the initial propulsion pressure, and the turning moment isregular on account of the relations ofthe power or impulse strokesthrough-' out the cycle. The transmission parts, also,

are fully utilized in transmitting, there being no idle strokes and'theroper quota of work being done on each stroke.

An important result in compound internal combustion engines is secured,also, by "an arrangement of high and lowpressure cylinders, such thateach high pressure cylinder lies alongside of the low plfessure cylinderto which" it exhausts, in that the ports or 'pipes throu h which theexhaust gasespass'in'expandin from a high pressure into a low pressurecy inder may Jbe made direct and very .short,;so as to exp ,se to theexpanding gases the minimum of cooling surface and secure simplicity inthe high pressure exhaust piping and valve mechanism. {The arrangeseaerrment of cylinders shown. and above de scribed, with two high pressurecylinders on one side and two low pressure cylinders on the other side,is preferred for securing this result, well as securing importantresults by the special" cycle it permits, but this teatn re of arrangingthe cylinders of a tour cycle compound engine with two cylinders.tandem011 each side and each high pressurecylinder placed alongside the lowpressure cylinder to which exhausts, forms a specific feature oi thepresent invention, independently of the particular arrangement ofcylinders or special cycle shown and described. I

The cylinders will be so proportioned and such pressure in the tank K bemaintained by the low pressure pistons, as to secure the initial andterminal pressures in the high pressure cylinders required for theeiiective operation of the low pressure cylinders by the exhaust fromthe high pressure cylinders, according to the running conditions oftheengine.

. It will be understood that the invention is not to be limited to aninternal combustion engine of any special class or using a charge ofl'uel of any special character, or securing combustion in any specialmanner, butthat the invention, as defined by the claims, is applicablegenerally in internal combustion engines.

What I claim is 1. A compound internal combustion four cyclereciprocating engine, having two double acting hi h pressure cylindersarranged tan.- dem with their pistons on the same crank, coi'nbinationwith two double acting low pressure cylinders arranged tandem andsubstantially parallel with and beside the high pressure cylinders withtheir pistons on a second crank on the same shaft and at approximately180 from the high pressure crank.

2. In a compound internal combustion four cycle reciprocating engine,two double acting high pressure cylinders arranged tandem with theirpistons on the same crank, in combination with two double acting lowpressure cylinders arranged tandem and substantially parallel with andbeside the high pressure cylinders with their pistons on a second crank,on the same shaft and at approximately 180 from the high ,pressurecrank, and suitable passages and mechanism foroperating the highpressure pistons by the initial pressure of a charge and the lowpressure pistons by the exhaust from the corresponding ends of the highpressure cylinders.

3. In a compound internal combustion four cycle reciprocating engine,two double acting high pressure cylinders arranged tandem' With theirpistons on the same crank, in combination with two double acting lowpressure cylinders arranged tandem and substantially parallel with andbeside the high pressure cylinders with theirpistons ona second crank onthe same-shaft and atjap'; proximately 180 from the high pressure crank,and suitable passages and mechanism for operating the high pressurepistons by the initial pressure of a charge compressed. by the,

low pressure pistons andfurthencompressed on the high pressure conipr jion stroke and the low pressure pistons by exhaustl l'Qm'.tlic highpressure cylinders.

l. In a compound internal .con bustio r ,four cycle reciprocatingengine, two double acting high pressure cylinders arranged tan dem withtheir pistons on thesanrecrai combination with two double actinglowpressure cylinders arranged tandem and sub stantially parallel withandibeside the high pressure cylinders with, theicpi second crank on thesaiii "fhaft ant q proximately 180 from crank, and suitable passages andmechanism for operating the high pressure pistonsby the initial pressureof a charge and the low pressure pistons by the exhaust from thecorresponding ends of the high pressure cylinders, and arranged tosecure a high pressure power stroke in one end of one cylinder at eachstroke and with each high. pressure power stroke opposed by the backpressure of a high pressure exhaust stroke.

5. In a compound internal combustion four cycle reciprocating engine,two double acting high pressure cylinders arranged tandem with theirpistons on the same crank, in combination with two double acting lowpressure cylinders arranged tandem and substantially parallel with andbeside the high pressure cylinders with their pistons on a second crankon the same shaft and at approximately 180 from the high pressure crank,and suitable passages and mechanism for operating the high pressurepistons by the initial pressure of a charge compressed by the lowpressure pistons and further compressed on the high pressure compressionstroke, and the low pressure pistons by exhaust from the high pressurecylinders, and having the strokes of the four cylinders throughout thecycle arranged substantially as herein shown and described.

6. A compound internal combustion four cycle reciprocating engine havingtwo double acting high pressure cylinders and two double acting lowpressure cylinders arranged with two cylinders tandem on each of twocranks substantially 180 apart 011 the same shaft, and with each highpressure cylinder placed substantially parallel with and beside the lowpressure cylinder to which it exhausts, in combination withsuitablepassages and mechanism for operating the high pressure pistons by theinitial pressure of a charge and the low pressure pistons by the exhaustfrom the adjacent ends of the high pressure oy1- inders.

. high [pressure 7. A compound internal combustion four cyclereciprocating engine having two double acting high pressure cylindersand two double acting low pressure cylinders arranged with two cylinderstandem on each of two cranks substantially 180 apart on the same shaft,and with each high pressure cylinder placed substantially parallelul'ith and beside the low ressure cylinder towhich it exhausts, incombination with suitable passages and mechanism for operating the highpressure pistons by the initial pressure of a charge compressed by thelow pressure pistons and further compressed on the high pressurecompression stroke, and the low ressure pistons by the exhaust from thead acent ends of the high pressure cylinders.

8. A compound internal combustion four cycle reciprocating engine havingtwo double acting high, ressure cylinders and two double acting lowpressure cylinders arranged with two. cylinders tandem on each of twocranks stroke, means for supplying substantially 180 apart on the sameshaft, and with each high pressure cylinder placed substantiallyparallel with and beside the low pressure cylinder to which it exhausts,in combination with an air receiver into which the air is compressedfrom each end of the low pressure cylinders on their compression fuelunder regulated pressure, and suitable passages and mechanism for mixingair from the receiver with fuel and charging the high pressure cyl-'inders, delivering the exhaust from the high 1 pressure cylinders to thelow pressure cylinders, and compresslng air from the low pressurecylinders to the IGOGIVGI'.

' In testimony whereof, Ihave hereunto set my hand, in the presence oftwo subscribing witnesses.

CLARENCE N. SCOTT. Witnesses:

A.. E. BALLIN,

S. B. DAUGHERTY.

